Document event.h (API)

[babeltrace.git] / include / babeltrace / ctf-ir / visitor.h

#ifndef BABELTRACE_CTF_IR_VISITOR_H
#define BABELTRACE_CTF_IR_VISITOR_H

/*
 * BabelTrace - CTF IR: Visitor
 *
 * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * The Common Trace Format (CTF) Specification is available at
 * http://www.efficios.com/ctf
 */

#ifdef __cplusplus
extern "C" {
#endif

/**
@defgroup ctfirvisitor CTF IR visitor
@ingroup ctfir
@brief CTF IR visitor.

A CTF IR <strong><em>visitor</em></strong> is a function that you
can use to visit the hierarchy of a
\link ctfirtraceclass CTF IR trace class\endlink with
bt_ctf_trace_visit() or of a
\link ctfirstreamclass CTF IR stream class\endlink with
bt_ctf_stream_class_visit().

The traversal of the object's hierarchy is always done in a
pre-order fashion.

@sa ctfirstreamclass
@sa ctfirtraceclass

@file
@brief CTF IR visitor types and functions.
@sa ctfirvisitor

@addtogroup ctfirvisitor
@{
*/

/**
@struct bt_ctf_object
@brief A CTF IR object wrapper.

This structure wraps both a CTF IR object and its type
(see #bt_ctf_object_type). It is used in the visiting function.

You can use the bt_ctf_object_get_type() and
bt_ctf_object_get_object() accessors to get the type and wrapped
CTF IR object of a CTF IR object wrapper.

A CTF IR object wrapper has <strong>no reference count</strong>: do \em
not use bt_put() or bt_get() on it.

@sa ctfirvisitor
*/
struct bt_ctf_object;

/**
@brief	CTF IR object wrapper type.
*/
enum bt_ctf_object_type {
	/// Unknown (used for errors).
	BT_CTF_OBJECT_TYPE_UNKNOWN = -1,

	/// \ref ctfirtraceclass.
	BT_CTF_OBJECT_TYPE_TRACE = 0,

	/// \ref ctfirstreamclass.
	BT_CTF_OBJECT_TYPE_STREAM_CLASS = 1,

	/// \ref ctfirstream.
	BT_CTF_OBJECT_TYPE_STREAM = 2,

	/// \ref ctfireventclass.
	BT_CTF_OBJECT_TYPE_EVENT_CLASS = 3,

	/// \ref ctfirevent.
	BT_CTF_OBJECT_TYPE_EVENT = 4,

	/// Number of entries in this enumeration.
	BT_CTF_OBJECT_TYPE_NR,
};

/**
@brief	Visting function type.

A function of this type is called by bt_ctf_trace_visit() or
bt_ctf_stream_class_visit() when visiting the CTF IR object wrapper
\p object.

\p object has <strong>no reference count</strong>: do \em not use
bt_put() or bt_get() on it.

@param[in] object	Currently visited CTF IR object wrapper.
@param[in] data		User data.
@returns		0 on success, or a negative value on error.

@prenotnull{object}

@sa bt_ctf_trace_visit(): Accepts a visitor to visit a trace class.
@sa bt_ctf_stream_class_visit(): Accepts a visitor to visit a stream
	class.
*/
typedef int (*bt_ctf_visitor)(struct bt_ctf_object *object,
		void *data);

/**
@brief	Returns the type of the CTF IR object wrapped by the CTF IR
	object wrapper \p object.

@param[in] object	Object wrapper of which to get the type.
@returns		Type of \p object.

@prenotnull{object}

@sa bt_ctf_object_get_object(): Returns the object wrapped by a given
	CTF IR object wrapper.
*/
enum bt_ctf_object_type bt_ctf_object_get_type(struct bt_ctf_object *object);

/**
@brief	Returns the CTF IR object wrapped by the CTF IR object
	wrapper \p object.

@param[in] object	Object wrapper of which to get the wrapped
			CTF IR object.
@returns		CTF IR object wrapped by \p object.

@prenotnull{object}

@sa bt_ctf_object_get_type(): Returns the type of a given
	CTF IR object wrapper.
*/
void *bt_ctf_object_get_object(struct bt_ctf_object *object);

/** @} */

#ifdef __cplusplus
}
#endif

#endif /* BABELTRACE_CTF_IR_VISITOR_H */